Objects of continuous lengths, such as electrical wires arranged in electrical appliances, pipings, bar-shaped iron materials for construction works etc., are put in order by tying a plural number of thereof into each bundle using bands for clamping. Further, bands for clamping are also employed instead of the conventional tying strings in the case, e.g where open parts of sacks are closed after filling the contents.
As for bands for clamping, various forms have heretofore been proposed. As one of those, there is known such structure that comprises a band for tying to objects of continuous lengths or open parts of sacks and a head integrally formed therewith and having at one end of the band a hole for inserting the other end of the band, which structure is made of a flexible metal or plastic material, and which is further provided with engaging teeth on the band and either an engaging tongue having a teeth surface to be engaged with the above-described engaging teeth of the band provided on the inner surface of the insertion hole of the head or an engaging tongue to be engaged with the above-described engaging teeth on the exit surface of the insertion hole, so that the other end of the band is passed through the above-described insertion hole to form a loop, thereby tying the objects of continuous lengths into a bundle. However, with the conventional bands for clamping, for example, in a structure, as llustrated in FIGS. 1 A and B, in which a band (2) having engaging teeth (9) and a head (1) having an engaging protrusion (8) on the exit surface (5) of an insertion hole (6) are jointly provided, since the angle (.theta.) formed by an engaging surface (10) at one tooth tip (9a ) of the above-described engaging teeth and the surface (2a) of the band is often a right angle or larger, this has a disadvantage that the engagement between the above-described engaging protrusion (8) and said tooth tip (9a) of the engaging teeth (9) easily comes off and thus that even though objects of continuous lengths or the like (11) have been tightly tied into a bundle, it comes off and becomes useless. Furthermore, since the band (2) is jointly provided with the head (1), flexibility is poor and hence there is only little freedom for the up-and-down flexing motion of the head (1), it also had a disadvantage that, for instance, when tying a great number of objects of continuous lengths, the engagement of the tooth tip (9a) of the above-described engaging teeth (9) and the engaging protrusion (8) even more easily comes off.
As the result of our intensive study in order to find bands for clamping for objects of continuous lengths which have eliminated the disadvantages found with the conventional bands for clamping, it has now been discovered that by providing the tooth tips of the engaging teeth in the above-described band in a specific form and at the same time rendering flexibility by imparting improvement to the joint part between the band and the head, a clamping device having good tying properties can be obtained and accordingly this invention has been accomplished.